A root connected to water and (to a lesser extent) rivers for much of Tolkien’s life. It first appearance was as ᴱ√NENE “flow” in the Qenya Lexicon of the 1910s, though Tolkien marked both the root and the gloss with a “?”; it had derivatives like ᴱQ. nen “river, †water” and ᴱQ. nēnu “yellow water lily” (QL/65). Under this entry Tolkien noted that “nen water is perhaps different from nen river, which is from neře” (QL/65); elsewhere in QL Tolkien gave ᴱ√NERE² or ᴱ√NEŘE [NEÐE] as the basis for nen (nend-) “river”, a root he said was often confused with ᴱ√NESE “give to feed; feed, pasture; graze” (QL/66). In the contemporaneous Gnomish Lexicon he had G. nenn “(1) water, (2) river” and G. nendil “water fay” which were probably a blending of NENE and NEÐE, as well as G. nern “brook” from ✱nere¹ (GL/60), probably corresponding to ᴱ√NERE² from QL.
In The Etymologies of the 1930s Tolkien had unglossed ᴹ√NEN with derivatives like ᴹQ. nén/N. nen “water” and ᴹQ. nelle “brook” (Ety/NEN), whereas ᴱ√NERE² and ᴱ√NEÐE from the 1910s seems to have been abandoned. The primitive form √NEN or nē̆n “water” continued to appear regularly in Tolkien’s writings from the 1940s, 50s and 60s (PE17/52, 167; PE19/102; PE21/64, 79).